The disclosure of the following priority application is herein incorporated by reference:
Japanese Patent Application No. 2000-003799, filed Jan. 12, 2000.
1. Field of the Invention
The present invention relates to an optical device, such as binoculars, provided with an eye cup on the eyepiece portion.
2. Description of the Related Art
Conventionally, on the periphery of the eyepiece portion of binoculars is attached a cylindrical eye cup protruding from the eyepiece lenses toward an observer. The eye cup maintains a certain distance between the eyepiece lenses and the observer""s eye by the eye cup being applied to the face around the observer""s eye. The observer""s eye is thus positioned approximately at the pupil position of the optical system in the binoculars, and the observer can obtain a large field of view and stable observation. For an observer wearing glasses, the eye cup contacts to the surface of the glasses, and the distance between the eyepiece lenses and the observer""s eye becomes too large to secure proper observation. To remove this drawback, the eye cup is conventionally so constructed that it can be drawn by its rotation or can be turned over.
Additionally, each of the two eyepiece portions of the binoculars has a mechanism for independently moving its eyepiece lenses a certain amount in the optical axis direction for diopter adjustment.
Referring to FIG. 3, an eyepiece portion of binoculars provided with a via-rotation-drawable type eye cup will be specifically described. In the configuration of FIG. 3, eyepiece frame 22 is fixed on lens barrel body 21 of the binoculars. On the inner surface of eyepiece frame 22 is slidably disposed cylindrical eyepiece lens barrel 301. Inside of eyepiece lens barrel 301 are fixed intermediate lens 12 and outer lens 13 that constitute eyepiece lenses. On the outer surface of eyepiece lens barrel 301 is fixed cam pin 23. Linear slot 302 of which major axis is parallel to optical axis 10 is formed in eyepiece frame 22 at the position of cam pin 23. Cam pin 23 is engaged with eyepiece frame 22 by being inserted through linear slot 302. On the other hand, at the outer side of eyepiece frame 22 is disposed diopter ring 20. The inner surface of diopter ring 20 is slidably contacted with the outer surface of eyepiece frame 22. Also, spiral slot 20a spirally formed around optical axis 10 is formed in diopter ring 20, and the head of cam pin 23 is inserted in spiral slot 20a. Cam pin 23 is thus engaged also with diopter ring 20. It is to be noted that diopter ring 20 is fixed relative to eyepiece frame 22 with respect to the direction of optical axis 10 by positioning member 303. Accordingly, diopter ring 20 rotates around optical axis 10 but is fixed with respect to the direction of optical axis 10.
In such a configuration as FIG. 3, because cam pin 23 is engaged with both of spiral slot 20a of diopter ring 20 and linear slot 302 of eyepiece frame 22, cam pin 23 is moved in the direction of optical axis 10 within the range of linear slot 302 by being guided by spiral slot 20a when an observer rotates knurled portion 20b of diopter ring 20 around optical axis 10. Eyepiece lens barrel 301 on which cam pin 23 is fixed thus moves in the direction of optical axis 10, and diopter adjustment can be performed.
Further, in the configuration of the eyepiece portion of FIG. 3, an eye cup is constructed as follows. Specifically, at the outer side of diopter ring 20 is disposed cylindrical eyepiece sleeve 24. Eyepiece sleeve 24 is fixed on eyepiece frame 22. Accordingly, eyepiece sleeve 24 does not rotates even when diopter ring 20 rotates. On the outer side of this fixed eyepiece sleeve 24 is disposed eyepiece cam barrel 25. The inner surface of eyepiece cam barrel 25 is slidably contacted with the outer surface of eyepiece sleeve 24. Into eyepiece sleeve 24 is fixed eye cup drawing cam pin 304 so deep as to reach eyepiece frame 22. Spiral slot 25a spirally formed around optical axis 10 is formed in eyepiece cam barrel 25; the head of cam pin 304 is inserted in spiral slot 25a; and cam pin 304 is engaged with spiral slot 25a. Further the outer surface of eyepiece cam barrel 25 is covered with eyepiece rubber 26 to effect soft contact with the observer.
Thus, when the observer rotates eyepiece cam barrel 25 around optical axis 10, eyepiece cam barrel 25 covered with eyepiece rubber 26 integrally moves in the direction of optical axis 10 by spiral slot 25a being guided by the fixed cam pin 304. In this manner, the eye cup can be drawn and returned to the original position.
Next, referring to FIG. 2, an eyepiece portion of binoculars provided with a turn-over type eye cup will be described. The eyepiece portion of FIG. 2 has a multistage zooming function. Inner lens lever 27 and intermediate lens lever 28 are respectively moved, by a mechanism (not shown), to predetermined positions corresponding to a zoom magnification selected by an observer via a zoom lever (not shown) provided between the right and left lens barrel bodies 21. These predetermined positions are so set that at a higher magnification, the distance between inner lens 11 and intermediate lens 12 becomes larger and that at a lower magnification, the distance becomes shorter. Inner lens lever 27 supports claw 16a of inner lens outer frame 16. Inside of inner lens outer frame 16 is disposed inner lens frame 14 in which inner lens 11 is fixed. On the inner surface of inner lens outer frame 16 is provided a female screw; on the outer surface of inner lens frame 14 is provided a male screw; and both screws are screw-fitted. Thus, by inner lens frame 14 being rotated around optical axis 10, inner lens frame 14 moves, in the direction of optical axis 10, by an amount corresponding to its angle of rotation. Further, intermediate lens lever 28 supports claw 17a of intermediate lens outer frame 17. On the inner surface of intermediate lens outer frame 17 is screw-fitted intermediate lens frame 15 to which intermediate lens 12 is fixed. Thus, by intermediate lens frame 15 being rotated around optical axis 10, intermediate lens frame 15 moves, in the direction of optical axis 10, by an amount corresponding to its angle of rotation.
On the other hand, in the configuration of FIG. 2, eyepiece frame 22 is fixed on lens barrel body 21. On the inner surface of eyepiece frame 22 is screw-fitted outer lens frame 19 in which outer lens 13 is fixed. Thus, by outer lens frame 19 being rotated around optical axis 10, outer lens frame 19 moves, in the direction of optical axis 10, by an amount corresponding to its angle of rotation. Outer lens frame 19 is fixed, by screw 201, on diopter ring 20 rotatively disposed at the outer side of eyepiece frame 22. Thus, by diopter ring 20 being rotated, outer lens frame 19 rotates and moves, in the direction of optical axis 10, by an amount corresponding to its angle of rotation.
Furthermore, outer lens frame 19 has protruding portion 19a elongated in the direction of optical axis 10, and this protruding portion 19a is inserted into through hole 15b formed through intermediate lens frame 15. Consequently, rotation of intermediate lens frame 15 accompanies the rotation of outer lens frame 19. Also, intermediate lens frame 15 is provided with protruding portion 15a elongated in the direction of optical axis 10, and protruding portion 15a is inserted into through hole 14b formed through inner lens frame 14. Thus, rotation of inner lens frame 14 accompanies the simultaneous rotation of outer lens frame 19 and intermediate lens frame 15. Intermediate lens frame 15 and inner lens frame 14 move, via the rotation, by the same movement amount in the direction of optical axis 10 as that of outer lens frame 19 caused by its rotation. Accordingly, because, via the rotation of diopter ring 20, all of outer lens frame 19, intermediate lens frame 15, and inner lens frame 14 move in the same direction and by the same movement amount along optical axis 10, diopter adjustment can be performed. It is to be noted that because intermediate lens frame 15 and inner lens frame 14 move within the length of protruding portion 19a and protruding portion 15a, respectively, even when the zoom lever is operated, the engagement between intermediate lens frame 15 and protruding portion 19a and that engagement between inner lens frame 14 and protruding portion 15a are maintained even when zoom magnification is changed.
In the configuration of FIG. 2, the eye cup is constituted of eyepiece rubber 26 that covers diopter ring 20. During diopter adjustment, eyepiece rubber 26 integrally rotates with diopter ring 20. For an observer wearing glasses to observe, eye cup portion 26a of eyepiece rubber 26 is turned over to the side of diopter ring 20.
As described above, with respect to the eye cup, there have been a via-rotation-drawable type and a turn-over type constituted only of eyepiece rubber. The turn-over type eye cup, however, deteriorates, due to longtime use, in its repeatedly turned over portion of rubber, and cracks may occur in the portion. Besides, the via-rotation-drawable type eye cup is, in recent years, generally preferred from the viewpoint of design. However, although in the case of the eyepiece portion of a fixed magnification optical system without a zooming function as illustrated in FIG. 3, the via-rotation-drawable type eye cup has been realized in the past, such type eye cup has not yet been realized in the case of the eyepiece portion with a zooming function as illustrated in FIG. 2. This is because the eyepiece portion provided with a zooming function is complicated in structure, i.e., diopter ring 20 is disposed so as to extend to the eyepiece side end surface of outer lens frame 19, and the via-rotation-drawable eye cup configuration including eyepiece sleeve 24, cam pin 304, and eyepiece cam barrel 25 as illustrated in FIG. 3 could not be applied as it is. Also, any attempt, through some ingenuities, to attach a via-rotation-drawable eye cup to the configuration of FIG. 2 would result in a larger diameter than that of the eye cup from eyepiece rubber 26 by the amount required by the conceived via-rotation-drawable mechanism, and it is difficult to realize a compact via-rotation-drawable eye cup.
It is an object of the present invention to provide binoculars, while being provided with a zooming function in the eyepiece portion, having a compact via-rotation-drawable type eye cup.
In order to attain the above object, binoculars according to the present invention comprises: a pair of lens barrel bodies; a pair of eyepiece portions; at least one of the pair of eyepiece portions being provided with an eyepiece frame fixed on one of the lens barrel bodies, a plurality of eyepiece lenses, a diopter adjusting portion that moves all of the plurality of eyepiece lenses by the same movement amount in an optical axis direction, and a via-rotation-drawable type eye cup portion; the diopter adjusting portion including a cam pin fixed relative to the eyepiece frame and a diopter ring that is guided by the cam pin in the optical axis direction by rotating of the diopter ring around an optical axis to move all of the plurality of eyepiece lenses in the optical axis direction; and the eye cup portion including a cylindrical eye cup member that is rotatively disposed at an outer side of the diopter ring and is guided by the cam pin in the optical axis direction by rotating of the cylindrical eye cup member around the optical axis to move the eye cup portion in the optical direction.
In this binoculars, it is preferred that the at least one of the pair of right and left eyepiece portions is further provided with a zooming portion that moves at least one of the plurality of eyepiece lenses in the optical axis direction for zooming.
Also, it is preferred that a second cylindrical member is fixedly disposed, between the diopter ring and the cylindrical eye cup member, relative to the eyepiece frame, the diopter ring rotates while sliding along the inner surface of the second cylindrical member, and the cylindrical eye cup member rotates while sliding along the outer surface of the second cylindrical member.
Also, it is preferred that the diopter ring has a spiral slot that engages with the cam pin to be guided in the optical axis direction, and the cylindrical eye cup member has a spiral slot that engages with the cam pin to be guided in the optical axis direction.
Also, it is preferred that the eye cup portion includes an elastic member that covers the cylindrical eye cup member.
An optical device according to the present invention comprises: a pair of lens barrel bodies; a pair of eyepiece portions; at least one of the pair of eyepiece portions being provided with an eyepiece frame fixed on one of the lens barrel bodies, a plurality of eyepiece lenses, a diopter adjusting portion that moves all of the plurality of eyepiece lenses by the same movement amount in an optical axis direction, and a via-rotation-drawable type eye cup portion; the diopter adjusting portion including a cam pin fixed relative to the eyepiece frame and a diopter ring that is guided by the cam pin in the optical axis direction by rotating of the diopter ring around an optical axis to move all of the plurality of eyepiece lenses in the optical axis direction; and the eye cup portion including a cylindrical eye cup member that is rotatively disposed at an outer side of the diopter ring and is guided by the cam pin in the optical axis direction by rotating of the cylindrical eye cup member around the optical axis to move the eye cup portion in the optical direction.
In this optical device, it is preferred that the at least one of the pair of right and left eyepiece portions is further provided with a zooming portion that moves at least one of the plurality of eyepiece lenses in the optical axis direction for zooming.
Also, it is preferred that a second cylindrical member is fixedly disposed, between the diopter ring and the cylindrical eye cup member, relative to the eyepiece frame, the diopter ring rotates while sliding along the inner surface of the second cylindrical member, and the cylindrical eye cup member rotates while sliding along the outer surface of the second cylindrical member.
Also, it is preferred that the diopter ring has a spiral slot that engages with the cam pin to be guided in the optical axis direction, and the cylindrical eye cup member has a spiral slot that engages with the cam pin to be guided in the optical axis direction.
Also, it is preferred that the eye cup portion includes an elastic member that covers the cylindrical eye cup member.